In addition, the remote also includes a Play/Pause button, and Next/Previous Track buttons. There is no button on the remote for accessing menus on the Zune and this feature is sorely missed. A simple
"back" button to emulate the Zune's "back" button would have added considerable functionality.
On the back there is a 3.5mm headphone jack, a 3.5mm auxiliary input, a mini USB jack, an RCA composite video jack, and the connector for the 18v DC power supply.
The auxiliary input can be used with any MP3 player to hear that player's sound through the M604 speakers. The M604 comes with a short 3.5mm to 3.5mm patch cord specifically for this purpose. The M604 includes an accessory plate/bracket that will clip into the front dock and allow you to park any MP3 player prominently in front like the Zune.
The USB jack can be used with a USB cable (not included) to patch your Zune back to a PC for syncing. With wireless syncing now enabled on the Zunes there is not so much need for a direct connection to a PC.
A surprising feature is the composite video output. Using an RCA cable you can pipe your Zune's video content to any TV with a composite video input. With the Zune's video output switched ON (a few steps into the setup menu) your Zune's menu will appear on the TV set. You will still need to use the Zune's controls to maneuver through the menus.
The back also has three threaded holes. These are for an available wall mount. The wall mount does not come with the M604. I like the idea of mounting the M604 on the wall, say above your bed or perhaps below a wall-mounted TV.
For audio quality, the M604 sounds OK, but not great. Better than using the earplugs that came with the Zune. I'm used to listening to my music on my home stereo with full range speakers, and the lack of bass from the M604 is quite noticeable. A few speaker dock manufactures have realized this and added a sub woofer to their docks. There doesn't seem to be any way to do the same with the M604. Audio books and Podcasts sound as good as they'll get, since the human voice rarely goes low enough to exceed the speaker's low limit. FM radio on the Zune requires the earphone cable as an antenna, and without it does not pick up more than one or two channels. As such the dock and Zune look a little odd with the earphones coming out of the top of the Zune, yet the sound coming out of the speakers. 7 out of 10 for audio.
Videos appear soft and without crisp detail when viewed on a modern digital TV. Even the Zune's menu does not look very good on a TV. IN a movie with action of any type the effect is diminished, so I rate video performance via the composite cable a 7 out of 10
Aesthetically the M604 looks fine. I'm a product designer and more critical than most. I give the looks a 8 out of 10, with the potential improvement being a better paint job. A flat black grill and brushed metal surround to match the new Zune colors and textures would have been nicer. An emphasised 6" lower range speaker right in the middle would have been a nice touch acoustically AND aesthetically.
A little better than 7 out of 10 is the best I can do for an all-around rating. It is clear there must be better speaker/docks out there, although ones for the Zune series are hard to find. Remember that 7 is a C and average. I reserve the Bs and As for significantly better performers.
Feel free to leave comments. If you've used this dock or own any Zune I'd love to hear from you.